They're all good for different reasons:
Regular V8 - fine, however the potassium content in Low Sodium V8 is higher, so if you're getting plenty of sodium and need to increase potassium, go with the low sodium stuff.
V8 Splash tropical blend - increass EWCM
v8 v-fusion passionfruit and tangerine (600mg+potassium)
Hope that helps! :)